public Form1()
    {
        InitializeComponent();
        AIQuestionBank.LoadFromFile();
        lblFeedback.Text = "";
        PopulateAIList();
    }

    private void SetPlaceholder(TextBox txt, string placeholder)
    {
        txt.Text = placeholder;
        txt.ForeColor = Color.Gray;

        txt.GotFocus += (s, e) =>
        {
            if (txt.Text == placeholder)
            {
                txt.Text = "";
                txt.ForeColor = Color.Black;
            }
        };

        txt.LostFocus += (s, e) =>
        {
            if (string.IsNullOrWhiteSpace(txt.Text))
            {
                txt.Text = placeholder;
                txt.ForeColor = Color.Gray;
            }
        };
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        SetPlaceholder(txtOpt1, "Option 1");
        SetPlaceholder(txtOpt2, "Option 2");
        SetPlaceholder(txtOpt3, "Option 3");
        SetPlaceholder(txtOpt4, "Option 4");
        SetPlaceholder(txtAccepted, "Comma-separated answers");
    }

    private void PopulateAIList()
    {
        questionListBox.DataSource = null;
        var list = AIQuestionBank.Questions
            .Select((line, index) =>
            {
                var q = manager.ConvertAIToQuestion(line);
                return q != null ? $"{index + 1}. {q.QuestionText}" : $"{index + 1}. [Invalid]";
            }).ToList();
        questionListBox.DataSource = list;
    }

    // ==== Quản lý câu hỏi ====
    private void btnAdd_Click(object sender, EventArgs e)
    {
        string type = cmbType.SelectedItem?.ToString() ?? "";
        string questionText = txtQuestion.Text.Trim();

        if (string.IsNullOrWhiteSpace(type) || string.IsNullOrWhiteSpace(questionText))
        {
            lblFeedback.Text = "❌ Please select type and enter question text.";
            lblFeedback.ForeColor = Color.Red;
            return;
        }

        if (type == "Multiple Choice")
        {
            if (string.IsNullOrWhiteSpace(txtOpt1.Text) ||
                string.IsNullOrWhiteSpace(txtOpt2.Text) ||
                string.IsNullOrWhiteSpace(txtOpt3.Text) ||
                string.IsNullOrWhiteSpace(txtOpt4.Text) ||
                cmbCorrect.SelectedIndex < 0)
            {
                lblFeedback.Text = "❌ Please fill all options and choose correct answer.";
                lblFeedback.ForeColor = Color.Red;
                return;
            }
        }
        else if (type == "True/False")
        {
            if (!rTrue.Checked && !rFalse.Checked)
            {
                lblFeedback.Text = "❌ Please select True or False.";
                lblFeedback.ForeColor = Color.Red;
                return;
            }
        }
        else if (type == "Open Ended")
        {
            if (string.IsNullOrWhiteSpace(txtAccepted.Text))
            {
                lblFeedback.Text = "❌ Please enter accepted answers.";
                lblFeedback.ForeColor = Color.Red;
                return;
            }
        }

        if (type == "Multiple Choice")
        {
            string[] options = { txtOpt1.Text, txtOpt2.Text, txtOpt3.Text, txtOpt4.Text };
            int correctIndex = cmbCorrect.SelectedIndex;
            manager.AddQuestionFromUI("mcq", questionText, options, correctIndex, null, null);
        }
        else if (type == "True/False")
        {
            bool isTrue = rTrue.Checked;
            manager.AddQuestionFromUI("tf", questionText, null, 0, null, isTrue);
        }
        else if (type == "Open Ended")
        {
            string[] answers = txtAccepted.Text.Split(',').Select(x => x.Trim()).ToArray();
            manager.AddQuestionFromUI("open", questionText, null, 0, answers, null);
        }

        lblFeedback.Text = "✅ Added successfully.";
        lblFeedback.ForeColor = Color.Green;
        PopulateAIList();
    }

    private void btnEdit_Click(object sender, EventArgs e)
    {
        int idx = questionListBox.SelectedIndex;
        if (idx < 0)
        {
            lblFeedback.Text = "Please select a question to edit.";
            lblFeedback.ForeColor = Color.Red;
            return;
        }

        string type = cmbType.SelectedItem?.ToString() ?? "";
        string questionText = txtQuestion.Text.Trim();

        if (string.IsNullOrWhiteSpace(type) || string.IsNullOrWhiteSpace(questionText))
        {
            lblFeedback.Text = "❌ Please select type and enter question text.";
            lblFeedback.ForeColor = Color.Red;
            return;
        }

        string formatted = "";
        if (type == "Multiple Choice")
        {
            if (string.IsNullOrWhiteSpace(txtOpt1.Text) ||
                string.IsNullOrWhiteSpace(txtOpt2.Text) ||
                string.IsNullOrWhiteSpace(txtOpt3.Text) ||
                string.IsNullOrWhiteSpace(txtOpt4.Text) ||
                cmbCorrect.SelectedIndex < 0)
            {
                lblFeedback.Text = "❌ Please fill all options and choose correct answer.";
                lblFeedback.ForeColor = Color.Red;
                return;
            }
            string[] options = { txtOpt1.Text, txtOpt2.Text, txtOpt3.Text, txtOpt4.Text };
            formatted = manager.FormatAsAIEntry(new MultipleChoiceQuestion
            {
                QuestionText = questionText,
                Options = options,
                CorrectOption = cmbCorrect.SelectedIndex
            });
        }
        else if (type == "True/False")
        {
            if (!rTrue.Checked && !rFalse.Checked)
            {
                lblFeedback.Text = "❌ Please select True or False.";
                lblFeedback.ForeColor = Color.Red;
                return;
            }
            formatted = manager.FormatAsAIEntry(new TrueFalseQuestion
            {
                QuestionText = questionText,
                IsTrue = rTrue.Checked
            });
        }
        else if (type == "Open Ended")
        {
            if (string.IsNullOrWhiteSpace(txtAccepted.Text))
            {
                lblFeedback.Text = "❌ Please enter accepted answers.";
                lblFeedback.ForeColor = Color.Red;
                return;
            }
            formatted = manager.FormatAsAIEntry(new OpenEndedQuestion
            {
                QuestionText = questionText,
                AcceptedAnswers = txtAccepted.Text.Split(',').Select(a => a.Trim()).ToList()
            });
        }

        AIQuestionBank.Questions[idx] = formatted;

        lblFeedback.Text = "✅ Question updated successfully.";
        lblFeedback.ForeColor = Color.Green;
        PopulateAIList();
    }

    private void btnDelete_Click(object sender, EventArgs e)
    {
        int idx = questionListBox.SelectedIndex;
        if (idx < 0)
        {
            lblFeedback.Text = "Please select a question to delete.";
            lblFeedback.ForeColor = Color.Red;
            return;
        }

        AIQuestionBank.Questions.RemoveAt(idx);
        lblFeedback.Text = "Deleted successfully.";
        lblFeedback.ForeColor = Color.Green;
        PopulateAIList();
    }

    // ==== Chơi Quiz ====
    private void btnStartQuiz_Click(object sender, EventArgs e)
    {
        string targetType = rbMCQ.Checked ? "mcq" :
                            rbTrueFalse.Checked ? "tf" : "open";

        manager.ClearSummary();
        manager.StartQuiz(targetType, 5);
        if (manager.GetTotalQuestions() == 0)
        {
            lblAnswerFeedback.ForeColor = Color.Red;
            lblAnswerFeedback.Text = "❌ No questions available.";
            return;
        }

        ShowQuestion(manager.GetCurrentQuestion());
        lblYourAnswer.Text = "Your Answer: \nCorrect Answer: ";

        lblScoreOutside.Text = $"Score: {manager.GetScore()} / {manager.GetTotalQuestions()}";
        lblScore.Text = "";
        tabControl1.SelectedTab = tabQuiz;
        btnStartQuiz.Enabled = false;
    }

    private void btnNext_Click(object sender, EventArgs e)
    {
        Question currentQuestion = manager.GetCurrentQuestion();
        if (currentQuestion == null) return;

        string userAnswer = GetUserAnswer(currentQuestion);
        bool isCorrect = manager.SubmitAnswer(userAnswer);
        manager.SaveAnswerSummary(currentQuestion, userAnswer, isCorrect);

        lblAnswerFeedback.ForeColor = isCorrect ? Color.Green : Color.Red;
        lblAnswerFeedback.Text = isCorrect ? "✅ Correct!" : "❌ Incorrect!";
        lblYourAnswer.Text = $"Your Answer: {userAnswer}\nCorrect Answer: {currentQuestion.GetCorrectAnswer()}";
        lblScoreOutside.Text = $"Score: {manager.GetScore()} / {manager.GetTotalQuestions()}";

        if (manager.HasNextQuestion())
        {
            ShowQuestion(manager.GetCurrentQuestion());
        }
        else
        {
            lblAnswerFeedback.ForeColor = Color.Blue;
            lblAnswerFeedback.Text = "🎉 Quiz finished!";
            btnStartQuiz.Enabled = true;

            
            StringBuilder summary = new StringBuilder("===== Quiz Summary =====\n");
            
            lstSummary.Items.Clear();
            foreach (var s in manager.Summary)
            {
                lstSummary.Items.Add($"Q: {s.Question}");
                lstSummary.Items.Add($"Your Answer: {s.YourAnswer}");
                lstSummary.Items.Add($"Correct: {s.CorrectAnswer}");
                lstSummary.Items.Add($"Result: {(s.IsCorrect ? "Correct" : "Incorrect")}");
                lstSummary.Items.Add("-----------------------------------");
            }


        }
    }

    private string GetUserAnswer(Question currentQuestion)
    {
        if (currentQuestion is MultipleChoiceQuestion)
        {
            if (opt1_Quiz.Checked) return opt1_Quiz.Text;
            if (opt2_Quiz.Checked) return opt2_Quiz.Text;
            if (opt3_Quiz.Checked) return opt3_Quiz.Text;
            if (opt4_Quiz.Checked) return opt4_Quiz.Text;
        }
        else if (currentQuestion is TrueFalseQuestion)
        {
            if (opt1_Quiz.Checked) return "True";
            if (opt2_Quiz.Checked) return "False";
        }
        else if (currentQuestion is OpenEndedQuestion)
        {
            return txtAnswer_Quiz.Text.Trim();
        }
        return string.Empty;
    }

    private void ShowQuestion(Question q)
    {
        q.RenderToUI(lblQuestion_Quiz,
                     new[] { opt1_Quiz, opt2_Quiz, opt3_Quiz, opt4_Quiz },
                     txtAnswer_Quiz);

        lblAnswerFeedback.Text = "";
    }

    private void cmbType_SelectedIndexChanged(object sender, EventArgs e)
    {
        string type = cmbType.SelectedItem?.ToString() ?? "";
        grpMCQ.Enabled = false;
        grpTrueFalse.Enabled = false;
        grpOpen.Enabled = false;

        if (type == "Multiple Choice") grpMCQ.Enabled = true;
        else if (type == "True/False") grpTrueFalse.Enabled = true;
        else if (type == "Open Ended") grpOpen.Enabled = true;
    }

    private void lblYourAnswer_Click(object sender, EventArgs e)
    {

    }
}